Julii Cory (Corydoras julii): Ultimate Care Guide


Common Name(s)Julii Cory, Leopard Cory, Julii Corydoras,
Scientific NameCorydoras julii
OriginSouth America
Temperature75-84°F (24-29°C)
Size2-2.5 inches
Minimum Tank Size20 gallons
Food & DietOmnivorous diet
Lifespan5 years
Water pH6.0-7.5
Tank MatesZebra danio, Apistogramma Ramirezi, Bettas, Amano Shrimps, Tetras, Swordtails, Angelfish, and other Corydoras
BreedingSticky eggs are laid on plants, substrate, or rock
DiseaseMay be susceptible to infection on barbels.
Julii Cory
Julii Cory (Corydoras julii)

Julii Cory (Corydoras julii) is a peaceful community fish that prefer to be kept in a group. They are freshwater fish that are native to the flooded forests of the lower Amazon region. More specifically, they have been found in Parnaba River of Brazil. They can also be found in smaller creeks and small tributaries in the region.

The patterns on their body, help the fish camouflage as they blend in with the substrate. They have pale colored bodies that are covered with brown patterns.

These peaceful fish have wonderful personalities. They are also able to move their eyes, which can resemble a winking motion.

While they aren’t difficult fish to keep, it is important to understand their native habitat, optimum water parameter, compatible tank mates, and general care requirements. When properly cared for, they can breed in an aquarium as well.

Julii Cory Care

Julii Cory are hardy fish and they are easy to care for. They accept a relatively wide range of water conditions in regards to the water hardness and pH level. However, they do required well oxygenated water and they will not tolerate poor water quality that are high in nitrites and nitrates.

Therefore, an aquarium filter of adequate capacity is required. As a general rule of thumb, the filter flow rate should be six times the volume of the tank. For example, in a 20 gallon tank, the flow rate of the aquarium filter should be at least 180 GPH (gallons per hour).

In order to prevent the nitrites and nitrates from accumulating in the tank, the water should be changed regularly. A 10-20% water change should be done 1-2 times a week. A gravel vacuum can be used to siphon out the rotting material in the aquarium substrate.

The fish can be shy, so providing adequate places for the fish to hide is important. Hardscape such as driftwood can provide the shelter that it needs. Aquarium plants with large leaves can be beneficial as well. Since they do not like bright lighting, floating aquarium plants can help dim the light for them as well.

Julii Cory Temperature

The optimum temperature range for Julii Cory is 73-79°F (23-26°C).  However, they are known to survive in a wider range of temperature of 68-84°F (20-29°C). Since Julii Cory prefer cooler temperatures than some of the other Corydoras species, it is best to avoid temperatures above 84°F.

Julii Cory Water pH

The optimum water pH for Julii Cory is 6.0-7.5. The optimum alkalinity is between 3° and 10° dKH (54ppm to 180ppm).

While they are known to survive in waters outside of this range, the pH range should not stray too far from this range. Even if the water is within the optimum range, it should not fluctuate too suddenly. Any changes in the water parameters should be made gradually. Wild caught specimen are often used to lower pH levels within this range, or even below this range.

Julii Cory Size

Julii Cory are small fish that grow to 2-2.5 inches. They have a stocky body shape with a round nose and short skull. Their body color is pale, but it has dark isolated spots all over their body. The body length of the female should not be too different from the males. However, the body width of the female will be thicker in comparison to males.

Julii Cory Tank Size

The minimum tank size for Julii Cory is 20 gallons. While they are small fish, they prefer to be in a group of at least 6. Since the tank must be able to accommodate the entire group of fish, a tank smaller than 20 gallons is not recommended. Of course, a larger tank can be beneficial, especially if additional fish are kept.

How many Julii Cory can you keep in a 10 gallon tank?

Considering the general rule of thumb of “one gallon of fish per gallon of water,” you would be able to keep 4-5 Julii Cory in a 10 gallon tank. However, this is not recommended since a minimum of 6 Julii Cory should be kept together. A tank size of at least 20 gallons would be better.

Keep in mind that Julii Cory prefer highly oxygenated water as well. A small aquarium that is overstocked may be become unsustainable fairly quickly.

Julii Cory Food & Diet

Julii Cory are omnivorous fish that require a well-balanced diet. In an aquarium, they can be fed dry flake food, sinking pellets, frozen food, and live fish food. Live fish food that can be fed to them include bloodworms, tubifex, brine shrimp, daphnia, and white worms. They can be fed twice a day, and be fed as much as they’ll consume in approximately 3 minutes.

Does Julii Cory Eat Algae?

In general, Julii Cory will not eat algae that is growing in the aquarium. They may try to nibble on some algae growth, but don’t expect them to clean an algae covered wall. They will not solve an algae growth problem like a Siamese Algae Eater or Amano Shrimp would.

However, Julii Cory will feed on algae wafers. Feeding algae wafer regularly can be beneficial as part of their varied diet.

Julii Cory Lifespan

Julii Cory has an average lifespan of 5-7 years. They are known to live longer under optimal conditions. Providing a proper environment and regular care will contribute to a longer lifespan. In fact, many fish that are well taken care of in aquariums may live longer than specimen in the wild.

Julii Cory Tank Mates

Julii Cory gets along with other little catfish, small calm fish, and other community tank fish, as long as they are non-aggressive and friendly. Small tetras, danios, rasboras, dwarf cichlids, and any other small community fish are also good options for tank mates. Any huge or aggressive fish should be avoided.

Are Julii Cory Schooling fish?

Julii Cory Catfish is a calm schooling fish that gets along with a wide variety other micro aquarium animals, including dwarf cichlids and angelfish. Because its fragile barbels and underbelly can be damaged by coarse substrate, it should be kept in an aquarium with sand or very smooth gravel.

Julii Cory Tank Setup

A tank setup for Julii Cory should be able to accommodate their needs. Some of their needs include well-oxygenated water and to be kept in groups of 6 or more. Therefore, it is recommended to setup a 20 gallon tank or larger, as a foundation for a solid aquarium setup.

The tank can be designed with material that would be present in their natural habitat. In their native habitat in South America, they would be swimming among rocks, driftwood, caves, and submerged tree roots. Hardscape material that would mimic these environments would be ideal.

Aquarium filtration is another important aspect of the setup. Julii Cory prefer highly oxygenated waters, so there should be plenty of surface water movement. They are spend most of their time near the bottom of the aquarium in search of food. There aerated water must be able to reach the bottom of the tank. Therefore, water current is important as well. Despite their stocky body shape, they can be found swimming in water with fairly strong current.

They need some light, but they don’t like high intensity light. Be sure to provide some areas with shade, in order to allow the fish to hide as necessary.

Since they are constantly grazing the bottom of the tank, the aquarium substrate should be sand or other fine gravel. Smooth rock or gravel is acceptable as well. Sharp objects should be avoided.

Tank Mates for Julii Cory

Julii Cory are peaceful community fish, so they are compatible with many fish of similar size and temperament. Fish that are compatible as tank mates for Julii Cory include many species of Tetras, Zebra Danio, Swordtails, Apistogramma Ramirezi, Betta fish, Amano Shrimp, Angelfish, and other Corydoras species.

Betta fish and Julii Cory are compatible and this may be surprising to some, considering how aggressive Betta fish can be. While Betta fish can be attack other fish, this aggression is usually reserved to other male Betta fish or other colorful fish that resemble male Betta fish. Since Julii Cory do not look similar to a Betta fish, this is usually not an issue. In addition, both fish occupy different levels of the aquarium, so this will contribute to their compatibility. Betta fish spend most of their time in the middle or top of the aquarium and Julii Cory spend most of their time near the bottom of the aquarium.

Shrimp and Julii Cory are also compatible as tank mates. This includes popular freshwater shrimp species such as Amano Shrimp and Cherry Shrimp. While they both occupy the bottom section of the aquarium, they are both very peaceful. Therefore, there should be no issues with compatibility.

Incompatible Tank Mates for Julii Cory

Julii Cory is generally incompatible with large fish that are aggressive. This includes fish such as Oscar fish, Green Terror Cichlid, Jaguar Cichlid, Flowerhorn fish.

Julii Cory Breeding

Julii Cory can be bred in an aquarium, and they exhibit breeding behavior that is similar to other Corydoras species.

They are egg spawners, but the parents are known to eat eggs after spawning. Therefore, it is important to separate the parents from the eggs after spawning. In order to breed these fish at scale, setting up a breeding tank will be necessary.

In the breeding tank, 2-3 males and 1 female fish can be added. Large water changes of 50-70 percent will encourage spawning. Slightly colder water and highly oxygenated water can trigger spawning as well. A pump female that is full of eggs may start spawning under the right conditions. If the fish do not spawn, simply repeat the process.

If successful, the female fish will lay her eggs on the plants or tank glass. The laid eggs are fertilized by the male fish. After the spawn, the parents should be removed from the tank before they start eating the eggs.

Julii Cory eggs will hatch after 3-5 days. During this time, keep a clean environment in the aquarium to prevent eggs from getting infected with fungus. Some breeders have been able to prevent fungal infection by adding a few drops of methylene blue to the tank water.

After the eggs hatch, the fry will consume their yolk sack for a period of 3-4 days. After that, the fry will start swimming. They will consume small food such as Vinegar Eels, Brine Shrimp nauplii, and other fry food.

Julii Cory Male or Female

Distinguishing between a male and female Julii Cory can be done by comparing their body shape. A female Julii Cory will have a thicker body when compared to males, especially when they are full of eggs. By looking at the fish from above, the difference will be quite obvious.

Julii Cory Disease

Julii Cory are quite hardy, and they aren’t prone to any particular disease. However, they aren’t immune to disease, so proper care is necessary. High nitrate levels can result in infection, especially when they have an injured barbel.

In addition, since they lack scales, they are extremely susceptible to salt, chemicals, and medications. This means that keeping clean water and stable conditions to prevent disease is very important.

Are Julii Cory Poisinous?

Julii Cory is not a highly poisonous fish, but they are known to possess a low level toxin in their axillary gland. It is reported that the low level toxin may irritate the skin. They also have pointed pectoral fins that will stiffen when they are threatened. Therefore, they should be handled with caution. These characteristics are not unique to Julii Cory since similar characteristics can be observed in many other Corydoras species.

Where can I Find Julii Cory for Sale?

Julii Cory is often available in local fish stores and online retailers. However, are usually available for $5-10 USD.

However, many fish that are labelled as Julii Cory are actually False Julii Cory. Therefore, if you wish to purchase true Julii Cory, it may be worth verifying the exact species of the fish.

Julii Cory vs False Julii Cory

Julii Cory (Corydoras julii) and False Julii Cory (Corydoras trilineatus) look very similar, but they do have differences in their markings.

Julii Cory have spotted markings on their body and head. Therefore, they are also called Leopard Cordoras as well. In contrast, False Julii Cory have reticulations in their markings on the body and head.

In addition the stripes on their body is different as well. The stripes on the body of False Julii Cory are substantially more prominent and solid than those on Julii Cory.

While both fish are native to South America, Julii Cory originate from the lower region of the Amazon River Basin. In contrast, False Julii Cory originate from the upper region of the Amazon River Basin.

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